nirmaladasar.files.wordpress.com€¦ · Web viewEXAMINATION PAPERS – 2008. CBSE (Delhi) SET–I. Time allowed: 3 hours. Maximum marks: 70. General Instructions: All questions

EXAMINATION PAPERS – 2008

CBSE (Delhi)

SET–I

Time allowed: 3 hoursMaximum marks: 70

General Instructions:

(i) All questions are compulsory.

(ii) The question paper consists of four sections A, B, C and D. Section A contains 8 questions of 1 mark each, Section B is of 10 questions of 2 marks each, Section C has 9 questions of 3 marks each whereas Section D is of 3 questions of 5 marks each.

(iii) There is no overall choice. However, an internal choice has been provided in one question of 2 marks, one question of 3 marks and all the three questions of 5 marks weightage. A student has to attempt only one of the alternatives in such questions.

(iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.

SECTION–A

1. What causes speciation according to Hugo de Vries?

2. When and why do some animals like frogs hibernate?

3. List any two economically important products for humans obtained from Apis indica.

4. Name the Indian variety of rice patented by an American company.

5. What role do macrophages play in providing immunity to humans?

6. Name the parts ‘A’ and ‘B’ of the transcription unit given below.

Structural gene

3'

A

3'

B

7. Name the world’s most problematic aquatic weed. What is the nature of the water body in which the weeds grow abundantly?

8. What is the major difference you observe in the offsprings produced by asexual reproduction and in the progeny produced by sexual reproduction?

SECTION–B

9. The flower of brinjal is referred to as chasmogamous while that of beans is cleistogamous. How are they different from each other?

10. Name the interaction in each of the following:

(a) Cuckoo lays her eggs in the crow’s nest.

(b) Orchid grows on a mango tree.

(c) Ticks live on the skin of dogs.

(d) Sea anemone is often found on the shell of hermit crab.

11. A man with blood group A married a woman with B group. They have a son with AB blood group and a daughter with blood group O. Work out the cross and show the possibility of such inheritance.

OR

The male fruit fly and female fowl are heterogametic while the female fruit fly and the male fowl are homogametic. Why are they called so?

12. Why is using tobacco in any form injurious to the health? Explain.

13. Differentiate between a detritivore and a decomposer giving an example of each.

14. A mother of one year old daughter wanted to space her second child. Her doctor suggested CuT. Explain its contraceptive actions.

15.

a

DNA

b

DNA

A

A

T

T

C

G

G

C

T

T

A

A

Study the linking of DNA fragments shown above:

(i) Name ‘a’ DNA and ‘b’ DNA.

(ii) Name the restriction enzyme that recognises this palindrome.

(iii) Name the enzyme that can link these two DNA fragments.

16. What is divergent evolution? Explain taking an example of plants.

17. Name the blank spaces a, b, c and d in the table given below:

Type of Microbe

Name

Commercial Product

Fungus

a

Penicillin

Bacterium

Acetobacter aceti

b

c

Aspergillus niger

Citric acid

Yeast

d

Ethanol

18. Thermal power plants are inevitable in an industrial and densely populated country like ours. What harm do they do to the environment? Also mention any precaution that could be taken to save our environment.

SECTION–C

19. Draw a labelled diagram of the microscopic structure of a human sperm.

20. Expand MOET. Explain the procedure of this technology in cattle improvement.

21. One of the codons on mRNA is AUG. Draw the structure of tRNA adapter molecule for this codon. Explain the uniqueness of this tRNA.

22. Study the population growth curves in the graph given below and answer the questions that follow:

Population density (N)

a

K

b

Time (t)

(i) Identify the growth curves ‘a’ and ‘b’.

(ii) Which one of them is considered a more realistic one and why?

dN

K N

(iii) If

= rN

is the equation of the logistic growth curve, what does K stand for?

dt

K

(iv) What is symbolised by N?

23. How and why is the bacterium Thermus aquaticus employed in recombinant DNA technology? Explain.

OR

(a) What are “molecular scissors”? Give one example.

(b) Explain their role in recombinant DNA technology.

24. Given below is a part of the template strand of a structural gene:

TACCAT TAG GAT

(a) Write its transcribed mRNA strand with its polarity.

(b) Explain the mechanism involved in initiation of transcription of this strand.

25. (i) How and at what stage does Plasmodium enter into a human body?

(ai) With the help of a flow-chart, only show the stages of asexual reproduction in the life cycle of the parasite in the infected human.

(bi) Why does the victim show symptoms of high fever?

26. It has been recorded that the temperature of the earth’s atmosphere has increased by 0.6°C.

(a) What has caused this increase?

(b) Explain its consequences.

27. Explain the pattern of inheritance of haemophilia in humans. Why is the possibility of a human female becoming a haemophilic extremely rare? Explain.

SECTION–D

28. Draw a labelled diagram of the sectional view of a mature pollen grain in angiosperms. Explain the functions of its different parts.

OR

Give a schematic representation of oogenesis in humans. Mention the number of chromosomes at each stage. Correlate the life phases of the individual with the stages of the process.

29. (a) Mention the role of vectors in recombinant DNA technology. Give any two examples.

(b) With the help of diagrammatic representation only, show the steps of recombinant DNA

technology.

OR

(a) What is plasmid?

(b) What is meant by ADA deficiency? How is gene therapy a solution to this problem? Why is not a permanent cure?

30. Explain Hershey-Chase experiment. What was proved through this experiment?

OR

(a) A true breeding pea plant, homozygous for inflated green pods is crossed with another pea plant with constricted yellow pods (ffgg). What would be the phenotype and genotype of F1 and F2 generations? Give the phenotype ratio of F2 generation.

(b) State the generalisation proposed by Mendel on the basis of the above mentioned cross.

SET–II

(Uncommon Questions to Set I)

SECTION–A

2. Which one of the two, stenothermals or eurythermals, shows wide range of distribution on earth and why?

5. Recently chikungunya cases were reported from various parts of the country. Name the vector responsible.

6. Name the components ‘a’ and ‘b’ in the nucleotide with a purine, given below:

H

a C

H

b

8. Name the technique used for separating DNA fragments in the laboratory.

SECTION–B


(a) Cuscuta growing on a shoe flower plant.

(b) Mycorrhizae living on the roots of higher plants.

(c) Clown fish living among the tentacles of sea anemone.

(d) Koel laying its eggs in crow’s nest.

17. Name the blank spaces a, b, c and d given in the following table:

Type of Microbe

Name

Commercial Product

Bacterium

a

Lactic acid

Fungus

b

Cyclosporin A

c

Monascus purpureus

Statins

Fungus

Penicillium notatum

d

SECTION–C

21. The length of a DNA molecule in a typical mammalian cell is calculated to be approximately 2.2 metres. How is the packaging of this long molecule done to accommodate it within the nucleus of the cell?

24. Draw a labelled diagram of sectional view of a human ovary showing various stages of follicles growing in it.

27. Why should biological control of pests and pathogens be preferred to the conventional use of chemical pesticides? Explain how the following microbes act as biocontrol agents:

(a) Bacillus thuringiensis(b) Nucleopolyhedrovirus

SECTION–D

30. (a) Draw a diagrammatic sketch of the sectional view of a typical anatropous ovule.

(b) List the components of the embryo sac and mention their fate on fertilisation.

OR

(a) Give a schematic representation of spermatogenesis in humans.

(b) At which stage of life does gametogenesis begin in human male and female respectively?

(c) Name the organs where gametogenesis gets completed in human male and female respectively.

SET–III

(Uncommon Questions to Set I and II)

SECTION–A

1. What causes swelling of the lower limbs in patients suffering from filariasis?

4. List any two adaptive features evolved in parasites enabling them to live successfully on their hosts.

6. Name the types of synthesis ‘a’ and ‘b’ occurring in the replication fork of DNA as shown

below:

5'

is

s

e

th

n

y

a

s

b

s y nt h e s i s

SECTION–B


(a) Ascaris worms living in the intestine of human.

(b) Sucker fish attached to the shark.

(c) Smaller barnacles disappeared when Balanus dominated in the coast of Scotland.

(d) Wasp pollinating fig inflorescence.

17. Name the blank spaces a, b, c and d given in the following table:

Type of Microbe

Name

Commercial Product

Bacterium

a

Clot buster enzyme

b

Aspergillus niger

Citric acid

Fungus

Trichoderma polysporum

c

Bacterium

d

Butyric acid

SECTION–C

20. Explain the process of charging of tRNA. Why is it essential in translation?

24. How do organisms manage with stressful conditions existing in their habitat for short duration? Explain with the help of one example each.

25. A non-haemophilic couple was informed by their doctor that there is possibility of a haemophilic child be born to them. Explain the basis on which the doctor conveyed this information. Give the genotypes and the phenotypes of all the possible children who could be born to them.

SECTION–D

28. A true breeding pea plant homozygous for axial violet flowers is crossed with another pea plant with terminal white flowers (aavv).

(a) What would be the phenotype and genotype of F1 and F2 generations?

(b) Give the phenotypic ratio of F2 generation.

(c) List the Mendel’s generalisations that can be derived from the above cross.

OR

(a) Explain Griffith’s series of experiments where he witnessed transformation in bacteria he worked with.

(b) Name the scientists responsible for determining the biochemical nature of “transforming principle” in Griffith’s experiments. What did they prove?


CBSE (All India)

SET–I




(ii) The question paper consists of four sections A, B, C and D. Section A contains 8 questions of

1 mark each, Section B is of 10 questions of 2 marks each, Section C has 9 questions of

3 marks each whereas Section D is of 3 questions of 5 marks each.

(iii) There is no overall choice. However, an internal choice has been provided in one question of

2 marks, one question of 3 marks and all the three questions of 5 marks weightage. A student has to attempt only one of the alternatives in such questions.


SECTION–A

1. Name any two vertebrate body parts that are homologous to human forelimbs.

2. When and why do some animals like snails go into aestivation?

3. What is the economic value of Spirulina?

4. What was the speciality of the milk produced by the transgenic cow Rosie?

5. How do neutrophils act as a cellular barrier to pathogens in humans?

6. Mention the polarity of the DNA strands a—b and c—d shown in the replicating fork given

below.

bd

a c

7. Mention any two significant roles predation plays in nature.

8. Why is the polar region not a suitable habitat for tiny humming birds?

SECTION–B

9. (a) Expand IUD.

(b) Why is hormone releasing IUD considered a good contraceptive to space children?





(d) Koel laying her eggs in crow’s nest.

11. A plant of Antirrhinum majus with red flowers was crossed with another plant of the same species with white flowers. The plants of the F1 generation bore pink flowers. Explain the pattern of inheritance with the help of a cross.

OR

A woman with blood group O married a man with AB group. Show the possible blood groups of the progeny. List the alleles involved in this inheritance.

12. Why do sports persons often fall victim to cocaine addiction?

13. State the difference between the first trophic levels of detritus food chain and grazing food chain.

14. Coconut palm is monoecious while date palm is dioecious. Why are they called so?

15. How can DNA segments, separated by gel electrophoresis, be visualised and isolated?

16. How do Darwin’s finches illustrate adaptive radiation?

17. Name the blank spaces a, b, c and d from the table given below:

Type of Microbe

Name

Commercial Product

Bacterium

a

Lactic acid

Fungus

b

Cyclosporin A

c

Monascus purpureus

Statin

Fungus

Penicillium notatum

d

18. DDT content in the water of a lake that supplies drinking water to the nearby villages, is found to be 0.003 ppm. The kingfishers of that area were reported to have 2 ppm of DDT. Why has the concentration increased in these birds? What harm will this cause to the bird population? Name the phenomenon.

SECTION–C

19. (a)

Ovarian hormone levels

1

Estrogen

Progesterone

5 10 15 20 25 29 Days

Read the graph given above and correlate the uterine events that take place according to the hormonal levels on:

(i) 6–15 days

(ii) 16–25 days

(iii) 26–28 days (if the ovum is not fertilised)

(b) Specify the sources of the hormones mentioned in the graph.

20. Explain the role of baculoviruses as biological control agents. Mention their importance in organic farming.

21. (a) Draw the structure of the initiator tRNA adaptor molecule.

(b) Why is tRNA called an adaptor molecule?

22.


K

a

b

Time (t)

Study the population growth curves shown above:

(i) Identify curves ‘a’ and ‘b’.

(ii) Mention the conditions responsible for the curves ‘a’ and ‘b’ respectively.

(iii) Give the necessary equation for the curve ‘b’.

23. Why is Agrobacterium tumefaciens a good cloning vector? Explain.

OR

Explain the importance of (a) ori, (b) amp R and (c) rop in the E. coli vector shown below:

Eco R I

Cla I

Hind III

Pvu I

Pst I

BamH I

ampR

tetR

Sal I

pBR322

ori

rop

Pvu II

24.

a

b

U A C G A G

A G A U U U

Study the mRNA segment given above which is complete to be translated into a polypeptide chain.

(i) Write the codons ‘a’ and ‘b’.

(ii) What do they code for?

(bi) How is peptide bond formed between two amino acids in the ribosome?

25. (a) Name the infective stage of Plasmodium which Anopheles mosquito takes in along with the blood meal from an infected human.

(b) Why does the infection cause fever in humans?

(c) Give a flow chart of the part of the life-cycle of this parasite passed in the insect.

26. A factory drains its waste water into the nearby lake. It has caused algal bloom.

(a) How was the algal bloom caused?

(b) What would be the consequences?

(c) Name the phenomenon that caused it.

27. Study the given pedigree chart and answer the questions that follow:

(a) Is the trait recessive or dominant?

(b) Is the trait sex-linked or autosomal?

(c) Give the genotypes of the parents in generation I and of their third and fourth child in generation II.

SECTION–D

28. (a) Draw a schematic labelled diagram of a fertilised embryo sac of an Angiosperm.

(b) Describe the stages in embryo development in a dicot plant.

OR

(a) Draw a labelled diagram of a sectional view of human seminiferous tubule.

(b) Differentiate between gametogenesis in human males and females on the basis of:

(i) time of initiation of the process.

(ii) products formed at the end of the process.

29. Explain the steps involved in the production of genetically engineered insulin.

OR

(a) Name the nematode that infests and damages tobacco roots.

(b) How are transgenic tobacco plants produced to solve this problem?

30. What is ‘semi-conservative’ DNA replication? How was it experimentally proved and by whom?

OR

A homozygous tall pea plant with green seeds is crossed with a dwarf pea plant with yellow seeds:

(i) What would be the phenotype and genotype of F1?

(ii) Work out the phenotypic ratio of F2 generation with the help of a Punnett Square.

SET–II

(Uncommon Questions to Set–I)

SECTION–A

2. Between amphibians and birds, which will be able to cope with global warming? Give reasons.

3. Name the two types of cells in which the HIV multiplies after gaining entry into the human body.

7. A multinational company outside India tried to sell new varieties of turmeric without proper rights. What is such an act referred to?

SECTION–B

10. Certain species of wasps are seen to frequently visit flowering fig trees. What type of interaction is seen between them and why?


Type of Microbe

Name

Commercial Product

Bacterium

a

Clot buster enzyme

b

Aspergillus niger

Citric acid

Fungus

Trichoderma polysporum

c

Bacteria

d

Butyric acid

SECTION–C

20. Name the pathogen that causes amoebiasis in humans. Give the symptoms and the mode of transmission of the disease.

22. How does Darwin’s theory of Natural Selection explain the appearance of new forms of life on earth?

23. How is the bacterium Thermus aquaticus employed in recombinant DNA technology?

OR

DNA being hydrophilic cannot pass through the cell membrane of a host cell. Explain how does recombinant DNA get introduced into the host cell to transform the latter.

SECTION–D

29. A tall pea plant with yellow seeds (heterozygous for both the traits) is crossed with a dwarf pea plant with green seeds. Using a Punnett square work out the cross to show the phenotypes and the genotypes of F1 generation.

OR

(a) Why is DNA molecule a more stable genetic material than RNA? Explain.

(b) “Unambiguous”, “degenerate” and “universal” are some of the salient features of genetic code. Explain.

SET–III

(Uncommon Questions to Set–I and II)

SECTION–A

3. Suggest any two techniques which can help in early detection of bacterial viral infections much before the symptoms appear in the body.

6. Mention the carbon positions to which the nitrogenous base and the phosphate molecule are respectively linked in the nucleotide given below:

Phosphate

H

PC

H

S

Base B

7. Given below are some human organs. Identify one primary and one secondary lymphoid organs: Liver, Thymus, Stomach, Thyroid, Tonsils.

SECTION–B

10. The ‘clown’ fish lives among the tentacles of sea anemone. What is this interaction between them called and why?


Type of Microbe

Scientific Name

Product

Medical Application

(i) Fungus

a

Cyclosporin

b

(ii) c

Monascus purpureus

Statin

d

SECTION–C

21. Name the type of immunity that is present at the time of birth in humans. Explain any two ways by which it is accomplished.

22. Study the graph given below and answer the questions that follow:

Concentration

Direction of flow of river

Sewage discharge

Dissolved oxygen

BOD

What is the relationship between dissolved oxygen and biochemical oxygen demand (BOD)?

(i) Mention their effect on aquatic life in the river.

26. Study the given pedigree chart and answer the questions that follow:

(a) Is the trait recessive or dominant?

(b) Is the trait sex-linked or autosomal?

(c) Give the genotypes of the parents shown in generation I and their third child shown in generation II and the first grandchild shown in generation III.

SECTION–D

28. Draw a labelled schematic structure of a transcription unit. Explain the function of each component in the unit in the process of transcription.

OR

A snapdragon plant homozygous for red flower when crossed with a white flowered plant of the same species produced pink flowers in F1 generation.

(a) What is this phenotypic expression called?

(b) Work out the cross to show the F2 generation when F1 was self-pollinated. Give the phenotypic and genotypic ratios of F2 generation.

(c) How do you compare the F2 phenotypic and genotypic ratios with those of Mendelian monohybrid F2 ratios?


CBSE (Foreign)

SET–I




(ii) The question paper consists of four sections A, B, C and D. Section A contains 8 questions of 1 mark each, Section B is of 10 questions of 2 marks each, Section C has 9 questions of 3 marks each whereas Section D is of 3 questions of 5 marks each.



SECTION–A

1. Pick out the ancestral line of angiosperms from the list given below: Conifers, seed ferns, cycads, ferns.

2. When and why do some animals go into hibernation?

3. What is the economic value of Saccharum officinarum?

4. What does the organisation GEAC check with reference to genetic engineering?

5. In what way are monocytes a cellular barrier in immunity?

6. What are ‘a’ and ‘b’ in the nucleotide with purine represented below?

H

a C

HS

b

7. About 200 species of Cichlid fish became extinct when a particular fish was introduced in Lake Victoria of Africa. Name the invasive fish.

8. What is the significance of the process of RNA interference (RNAi) in eukaryotic organisms?

SECTION-B


Item

What it Represents in the Plant

(i) Pericarp

a

(ii) b

cotyledon in seeds of grass family

(iii) Embryonal axis

c

(iv) d

remains of nucellus in a seed

10. In a particular plant species, majority of the plants bear purple flowers. Very few plants bear white flowers. No intermediate colours are observed. If you are given a plant with purple flowers, how would you confirm that it is a pure breed for that trait? Explain.

OR

A woman with B blood group married a man with A blood group. They had 2 sons and both had O group. Show the possibility of such an inheritance. List the alleles involved in determining the blood group.


(a) Clown fish living among the tentacles of sea anemone.

(b) Sucker fish lives attached to the shark.

(c) Smaller barnacles disappeared when Balanus dominated in the coast of Scotland.

(d) Wasp pollinating fig inflorescence.

12. Due to undue peer pressure a group of adolescents started using opioids intravenously. What are the serious problems they might face in future?

13. Construct a grazing food chain and detritus food chain using the following, with 5 links each: Earthworm, bird, snake, vulture, grass, grasshopper, frog, decaying plant matter.

14. How do surgical procedures prevent conception in humans? Mention the way it is achieved in human males.

15. The following illustrates the linking of DNA fragments:

a DNAb DNA

C

G

(i) Name ‘a’ and ‘b’ .

(ii) Complete the palindrome which is recognised by EcoRI.

(iii) Name the enzyme that can link the two DNA fragments.

16. How do Darwin and de Vries differ in their views on the mechanism of evolution of life on earth?

17. State the use of the following enzymes/acids produced by the microbes:

(i) Lipase

(ii) Lactic acid

(iii) Streptokinase

(iv) Pectinase

18. (a) Name the green house gases that caused global warming.

(b) Which of them has caused ozone hole and how?

SECTION-C

19. Study the figure given:

e

d

c

b

f

a

(i) Pick out and name the cells that undergo spermiogenesis.

(ii) Name ‘a’ and ‘b’ cells. What is the difference between them with reference to the number of chromosomes?

(iii) Pick out and name the motile cells.

(iv) What is ‘f’ cell? Mention its function.

(v) Name the structure of which the given diagram is a part.

20. Define totipotency of a cell. List the requirements if the objective is to produce somaclones of a tomato plant on commercial scale.

21. (a) One of the codons on mRNA is AUG. Draw the structure of tRNA adapter molecule for this codon.

(b) Name the RNA polymerase that transcribes tRNA in eukaryotes.

(c) What is unique about the amino acid this tRNA binds with?

22. Study the graph given below:


Ka

b

Time (t)

(i) What does the curve ‘a’ represent in the graph? What does ‘K’ stand for?

(ii) Which one of the two curves is considered a more realistic one for most of the animal population?

(iii) Which curve would depict the population of a species of deer if there are no predators in the habitat? Why is it so?

23. A vector is engineered with three features which facilitate its cloning within the host cell. List the three features and explain each one of them.

OR

Why are restriction endonucleases so called? Explain their role as ‘molecular scissors’ in

recombinant DNA technology.

24. What is hnRNA? Explain the changes hnRNA undergoes during its processing to form mRNA.

25. Name the malarial parasite. Where do the gametocytes of this parasite develop? Give a flow chart of its life-cycle in this host.

26. (a) Expand BOD.

(b) At a particular segment of a river near a sugar factory, the BOD is much higher than the normal level. What is it indicative of? What will happen to the living organisms in this part of the river?

(c) Under what conditions will the BOD be lowered in the river? How will it affect the aquatic life?

27. Study the pedigree chart given below showing the inheritance pattern of a human trait and answer the questions that follow:

I

II

III

(a) Give the genotype of the parents shown in generation I and of the son and daughter shown in generation II.

(b) Give the genotype of the daughters shown in generation III.

(c) Is the trait sex-linked or autosomal? Justify your answer.

SECTION-D

28. (a) Give a schematic representation of oogenesis in human female indicating the chromosomal number at each step. Mention at what stage of female life does each phase occur.

(b) Where would you look for coleoptile and coleorhiza? What function do they perform?

OR

(a) Draw a labelled schematic representation of a mature embryo sac of an angiosperm.

(b) Explain the role of ovarian hormones in inducing changes in the uterus during menstrual cycle.

(c) What triggers release of oxytocin at the time of parturition?

29. Explain the steps involved in the production of genetically engineered insulin. Why is insulin thus produced preferred to the one produced from non-human sources?

OR

(a) Why is Bacillus thuringiensis considered suitable for developing GM plants?

(b) Explain how it has been used to develop GM crops.

30. What is semiconservative replication of DNA? Explain how it was experimentally proved.

OR

(a) A true breeding pea plant homozygous for axial violet flowers is crossed with another pea plant with terminal white flowers (aavv). Work out the cross to show the phenotypes and genotypes of F1 and F2 generations along with the ratios.

(b) State the law that Mendel proposed on the basis of such a cross.

SET–II


SECTION-A

3. High fever, loss of appetite, stomach pain and constipation are some of the symptoms seen in a patient. How would the doctor confirm that the patient is suffering from typhoid and not amoebiasis?

6. Given below is a schematic representation of a lac operon in the absence of an inducer. Identify ‘a’ and ‘b’ in it.

p ip o o y a

‘b’

Repressor

mRNA

‘a’

7. State the principle on which ELISA works.

8. Name the pioneer species:

(i) on a bare rock

(ii) in a water body

SECTION-B

9. Name the blank spaces a, b, c and d in the table given below:

Name of the Drug

Plant Source

Or gan System Affected

(i)

a

Poppy plant

b

(ii)

Marijuana

c

d

11. Why is ‘Saheli’ considered to be an improved form of oral contraceptive for human females?

15. Give the sum total of all the allelic frequencies in a stable population. List any two factors which disturb the stability of a population. How does this disturbance affect the population?

SECTION-C

22. (a) What is micropropagation? Why are the plants produced by rnicropropagation called somaclones?

(b) Name the technique by which healthy plants can be recovered from the diseased plants.

26. Study the graph below and answer the questions which follow:


Ka

b

Time (t)

dN

(i) The curve ‘a’ is represented by the equation = rN. What does ‘r’ represent in the dt

equation and what is its importance?

(ii) Which one of the two curves is considered a more realistic one for most of the animal population?


SECTION-D

30. A true breeding pea plant, homozygous for inflated and green pods is crossed with another pea plant with constricted and yellow pods (ffgg).

(i) Work out the cross to show the phenotypes and genotypes of F1 and F2 generations. Give the phenotype ratio of F2 generation.

(ii) List the laws of Mendel which can be derived from such a cross.

OR

(i) Who explained the ‘transforming principle’ in an organism? How did the scientist perform the experiment to explain this principle?

(ii) How was the biochemical nature of the transforming material determined? Explain.

SET–III


SECTION-A

3. Give the scientific name of the pathogen causing malignant malaria in humans.

6. What are a and b in the transcription unit represented below?

3'

a

b

3'

SECTION–B

9. How do normal cells get transformed into cancerous neoplastic cells? Mention the difference between viral oncogenes and cellular oncogenes.





(d) Koel laying its eggs in crow’s nest.

11. How do ‘pills’ act as contraceptives in human females?

12. State Hardy–Weinberg principle of genetic equilibrium. Knowing that genetic drift disturbs this equilibrium, mention what does this disturbance in genetic equilibrium lead to.

SECTION–C

26. Study the graph given below and answer the questions which follow:


Ka

b

Time (t)

(i) The curve ‘b’ is described by the following equation:

dN

K – N

rN

dt

K

What does ‘K’ stand for in this equation? Mention its significance.

(ii) Which one of the two curves is considered a more realistic one for most of the animal populations?


27. Explain the advantages of inbreeding in cattle population. What effect does inbreeding depression have on cattle population and how is it overcome?

SECTION–D

30. What are transgenic animals? Explain any four ways in which such animals can be beneficial to humans.

Or

(a) What is a plasmid?

(b) What is meant by ADA deficiency? How is gene therapy a solution to this problem? Why is it not a permanent cure?


CBSE (Delhi)

SET–I



(I) All questions are compulsory.

(ii) The question paper consists of four sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C is of 9 questions of three marks each and Section D is of 3 questions of five marks each.



SECTION–A

1. Why hnRNA is required to undergo splicing?

2. The microscopic pollen grains of the past are obtained as fossils. Mention the characteristic of the pollen grains that makes it happen.

3. How does colostrum provide initial protection against diseases to new born infants? Give one reason.

4.

Crustaceans

b Other animal

groups

a

Name the unlablelled areas ‘a’ and ‘b’ of the pie chart (given above) representing the global biodiversity of invertebrates showing their proportionate number of species of major taxa.

5. Mention the type of evolution that has brought the similarity as seen in potato tuber and sweet potato.

6. Name the group of organisms and the substrate they act on to produce biogas.

7. Mention the pollinating agent of an inflorescence of small dull coloured flowers with well exposed stamens and large feathery stigma. Give any one characteristic of pollen grains produced by such flowers.

8. Name the organism commercially used for the production of single cell protein.

SECTION–B

9. Explain the contribution of Thermus aquaticus in the amplification of a gene of interest.

10.

a

b

(i) What does the above diagram illustrate?

(ii) Name the parts labelled ‘a’ and ‘b’.

(iii) Name the type of cells that produce this molecule.

11. Banana is a parthenocarpic fruit whereas oranges show polyembryony. How are they different from each other with respect to seeds?

OR

Where are fimbriae present in a human female reproductive system? Give their function.

12. How is the translation of mRNA terminated? Explain.

13. Explain accelerated eutrophication. Mention any two consequences of this phenomenon.

14. List the specific symptoms of amoebiasis. Name the causative organism.

15. A crane had DDT level as 5 ppm in its body. What would happen to the population of such birds? Explain giving reasons.

16. Describe the responsibility of GEAC, set up by the Indian Government.

17. During the secondary treatment of the primary effluent how does the significant decrease in BOD occur?

18. Study the figure given below and answer the questions:

i

p

o

z

y

a

mRNA

lac

mRNA

Enzymes

(a) How does the repressor molecule get inactivated?

(b) When does the transcription of lac mRNA stop?

(c) Name the enzyme transcribed by the gene ‘z’.

SECTION – C

19. Name the pioneer species on a bare rock. How do they help in establishing the next type of vegetation? Mention the type of climax community that will ultimately get established.

20. Study the figure given below and answer the questions that follow:

Inner

cell mass

a

(a) Name the stage of human embryo the figure represents.

(b) Identify ‘a’ in the figure and mention its function.

(c) Mention the fate of the inner cell mass after implantation in the uterus.

(d) Where are the stem cells located in this embryo?

21. Give the scientific name of the parasite that causes malignant malaria in humans. At what stage does this parasite enter the human body? Trace its life cycle in human body.

22. Draw a labelled schematic sketch of replication fork of DNA. Explain the role of the enzymes involved in DNA replication.

23. Explain the causes of global warming. Why is it a warning to mankind?

24. Haemophilia is a sex linked recessive disorder of humans. The pedigree chart given below shows the inheritance of haemophilia in one family. Study the pattern of inheritance and answer the questions given.

12

3

4

5

6

7

8

9

101112131415

(a) Give all the possible genotypes of the members 4, 5 and 6 in the pedigree chart.

(b) A blood test shows that the individual 14 is a carrier of haemophilia. The member numbered 15 has recently married the member numbered 14. What is the probability that their first child will be a haemophilic male?

OR

Inheritance pattern of ABO blood group in humans shows dominance, co-dominance and multiple allelism. Explain each concept with the help of blood group genotypes.

25.

Tasmanian wolf

Sugar glider

Tiger cat

Marsupial mole

Marsupial

radiation

Banded anteater

Koala

Marsupial rat

Bandicoot

WombatKangaroo

(a) Mention the specific geographical region where these organisms are found.

(b) Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region.

(c) Explain giving reasons the existence of placental wolf and Tasmanian wolf sharing the same habitat.

26.

Cla I

c

b

Pvu I

BamH I

Pst I

ad

pBR322

Sal I

ori

rop

Pvu II

(a) Identify the selectable markers in the diagram of E. coli vector shown above.

(b) How is the coding sequence of -galactosidase considered a better marker than the ones identified by you in the diagram? Explain.

27. Construct an ideal pyramid of energy when 1,000,000 joules of sunlight is available. Label all its trophic levels.

SECTION – D

28. Explain with the help of a diagram the development of a mature embryo sac from a megaspore mother cell in angiosperm.

OR

Study the following flow chart. Name the hormones involved at each stage. Explain their functions.

Hypothalamus

Pituitary

Testes

Sperms

29. (a) Explain the experiment performed by Griffith on Streptococcus pneumoniae. What did he conclude from this experiment?

(b) Name the three scientists who followed up Griffith’s experiments.

(c) What did they conclude and how?

OR

Two blood samples A and B picked up from the crime scene were handed over to the forensic department for genetic fingerprinting. Describe how the technique of genetic fingerprinting is carried out. How will it be confirmed whether the samples belonged to the same individual or to two different individuals?

30. One of the main objectives of biotechnology is to minimise the use of insecticides on cultivated crops. Explain with the help of a suitable example how insect resistant crops have been developed using techniques of biotechnology.

OR

(a) How is mature insulin different from proinsulin secreted by pancreas in humans?

(b) Explain how was human functional insulin produced using rDNA technology.

(c) Why is the functional insulin thus produced considered better than the ones used earlier by diabetic patients?

SET–II


SECTION–A

4. Why are the wings of a butterfly and of a bat called analogous?

8. How are the two following varieties of sugarcane different from each other?

(i) Saccharum barberi (ii) Saccharum officinarum

SECTION–B

11. Name the cell from which the endosperm of coconut develops. Give the characteristic features of endosperm of coconut.

OR

How does Cu-T act as an effective contraceptive for human females?

13. Nematode-specific genes are introduced into the tobacco plants using Agrobacterium vectors to develop resistance in tobacco plants against nematodes. Explain the events that occur in tobacco plant to develop resistance.

15. Egrets are often seen along with grazing cattle. How do you refer to this interaction? Give a reason for this association.

SECTION–C

24. Mention the target cells of luteinising hormone in human males and females. Explain the effect and the changes which the hormone induces in each case.

SECTION–D

29. (a) Draw a diagrammatic sectional view of human ovary showing different stages of oogenesis along with corpus luteum.

(b) Where is morula formed in humans? Explain the process of its development from zygote.

OR

How does the pollen mother cell develop into a mature pollen grain? Illustrate the stages with labelled diagrams.

30. How did Hershey and Chase prove that DNA is the hereditary material? Explain their experiment with suitable diagrams.

OR

Inheritance pattern of flower colour in garden pea plant and snapdragon differs. Why is this difference observed? Explain showing the crosses up to F2 generation.

SET–III


SECTION–A

3. Some allergens trigger sneezing and wheezing in human beings. What causes this type of response by the body?

5. Are the thorn of Bougainvillea and tendril of Cucurbita homologous or analogous? What type of evolution has brought such a similarity in them?

6. Mention the two additional processings which hnRNA needs to undergo after splicing so as to become functional.

8. Which of the following is a free living bacteria that can fix nitrogen in the soil?

Spirulina, Azospirillum, Sonalika

SECTION–B

10. Name the muscular and the glandular layers of human uterus. Which one of these layers undergoes cyclic changes during menstrual cycle? Name the hormone essential for the maintenance of this layer.

OR

Name the hormonal composition of the oral contraceptive used by human females. Explain how does it act as a contraceptive.

14. (a) What is “r” in the population equation given: dN/dt = rN

(b) How does the increase and the decrease in the value of ‘r’ affect the population size?

SECTION–C

19. (a) Name the respective forms in which the malarial parasite gains entry into (i) Human body and (ii) Body of female Anopheles.

(b) Name the hosts where the sexual and the asexual reproductions of malarial parasites occur respectively.

(c) Name the toxin responsible for the appearance of symptoms of malaria in humans. Why do these symptoms occur periodically?

SECTION–D

28. (a) What did Meselson and Stahl observe when

(i) they cultured E. coli in a medium containing 15NH4Cl for a few generations and centrifuged the content?

(ii) they transferred one such bacterium to the normal medium of NH4Cl and cultured for 2 generations?

(b) What did Meselson and Stahl conclude from this experiment? Explain with the help of diagrams.

(c) Which is the first genetic material? Give reasons in support of your answer

OR

You are given a red flower-bearing pea plant and a red flower-bearing snapdragon plant. How would you find the genotypes of these two plants with respect to the colour of the flower? Explain with the help of crosses. Comment upon the pattern of inheritance seen in these two plants.

29. (a) Draw a labelled diagram of a mature embryo sac.

(b) Why does a pollen grain possess two male gametes? Explain.

OR

(a) Draw a schematic diagram of a human sperm and label the cellular components. Give the functions of any three parts.

(b) Where are the sperm heads found embedded to survive after spermatogenesis?


CBSE (All India)

SET–I




(ii) The question paper consists of four sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C has 9 questions of three marks each whereas Section D is of 3 questions of five marks each.



SECTION–A

1. When and at what end does the ‘tailing’ of hnRNA take place?

2. Name the type of flower which favours cross pollination.

3. Name the type of cells the AIDS virus enters into after getting in the human body.

4. Name the unlabelled areas ‘a’ and ‘b’ of the pie chart representing the biodiversity of plants showing their proportionate number of species of major taxa.

Mosses Ferns

ab

Lichens

5. According to Hardy–Weinberg’s principle, the allele frequency of a population remains constant. How do you interpret the change of frequency of alleles in a population?

6. A boy of ten years had chicken-pox. He is not expected to have the same disease for the rest of his life. Mention how it is possible.1

7. Which one of the following is the baker’s yeast used in fermentation?

Saccharum barberi, Saccharomyces cerevisiae, Sonalika.

8. Why is bagging of the emasculated flowers essential during hybridisation experiments?

SECTION–B

9. What are recombinant proteins? How do bioreactors help in their production?

10. (a) Name the lymphoid organ in humans where all the blood cells are produced.

(b) Where do the lymphocytes produced by the lymphoid organ mentioned above migrate and how do they affect immunity?

11. Draw a vertical section of a maize grain and label (i) pericarp, (ii) scutellum, (iii) coleoptile and (iv) radicle.

OR

Where are the Leydig cells present? What is their role in reproduction?

12. Explain the dual function of AUG codon. Give the sequence of bases it is transcribed from and its anticodon.

13. Explain the cause of algal bloom in a water body. How does it affect an ecosystem?

14. List the specific symptoms of typhoid. Name its causative agent.

15. Name the pioneer and the climax species in a water body. Mention the changes observed in the biomass and the biodiversity of the successive seral communities developing in the water body.

16. How is DNA isolated in purified form from a bacterial cell?

17. Explain metastasis. Why is it fatal?

18.

i

p

o

z

y

a

Transcription

mRNA

lac

mRNA

Translation

X

Enzymes

Inducer

(a) Name the molecule ‘X’ synthesised by ‘i’ gene. How does this molecule get inactivated?

(b) Which one of the structural genes codes for -galactosidase?

(c) When will the transcription of this gene stop?

SECTION–C

19. Fertilisation is essential for production of seed, but in some angiosperms, seeds develop without fertilisation.

(i) Give an example of an angiosperm that produces seeds without fertilisation. Name the process.

(ii) Explain the two ways by which seeds develop without fertilisation.

20. Explain any three measures which will control vehicular air pollution in Indian cities.

21. (a) Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body when bitten by female Anopheles? Explain.

(b) Give the scientific name of the malarial parasite that causes malignant malaria in humans.

22.

b

c

a

d

(a) What is this diagram representing?

(b) Name the parts a, b and c.

(c) In the eukaryotes, the DNA molecules are organised within the nulceus. How is the DNA molecule organised in a bacterial cell in absence of a nucleus?

23. Ornithologists observed decline in the bird population in an area near a lake after the setting of an industrial unit in the same area. Explain the cause responsible for the decline observed.

24. Recently a girl baby has been reported to suffer from haemophilia. How is it possible? Explain with the help of a cross.

OR

What are satellite DNA in a genome? Explain their role in DNA fingerprinting.

25.

1234

(a) Write your observations on the variations seen in the Darwin’s finches shown above.

(b) How did Darwin explain the existence of different varieties of finches on Galapagos Islands?

26. Name and explain the techniques used in the separation and isolation of DNA fragments to be used in recombinant DNA technology.

27. The following graph represents the organismic response to a certain environmental condition (e.g., temperature):

level

a

b

Internal

External level

(i) Which one of these, ‘a’ or ‘b’, depicts conformers?

(ii) What does the other line graph depict?

(iii) How do these organisms differ from each other with reference to homeostasis?

(iv) Mention the category to which humans belong.

SECTION–D

28. How did Hershey and Chase prove that DNA is the hereditary material? Expain their experiment with suitable diagrams.

OR

A particular garden pea plant produces only violet flowers.

(a) Is it homozygous dominant for the trait or heterozygous?

(b) How would you ensure its genotype? Explain with the help of crosses.

29. How does the pollen mother cell develop into a mature pollen grain? Illustrate the stages with labelled diagrams.

OR

Study the flow chart given below. Name the hormones involved at each stage and explain their functions.

Hypothalamus

Pituitary

Ovary

Pregnancy

30. How is a transgenic tobacco plant protected against Meloidegyne incognitia? Explain the procedure.

OR

(a) Name the source of Taq polymerase. Explain the advantage of its use in biotechnology.

(b) Expand the name of the enzyme ADA. Why is this enzyme essential in the human body? Suggest a gene therapy for its deficiency.

SET–II

(Uncommon Questions to Set–I)

SECTION–A

1. Mention the strategy used to increase homozygosity in cattle for desired traits.

SECTION–B

9. MOET programme has helped in increasing the herd size of the desired variety of cattle. List the steps involved in conducting the programme.

11. Explain any two devices by which autogamy is prevented in flowering plants.

OR

Why do some women use “Saheli” pills?

18. Name the type of cells the AIDS virus first enters into after getting inside the human body. Explain the sequence of events that the virus undergoes within these cells to increase their progeny.

SECTION–C

19. Particulate and gaseous pollutants along with harmless gases are released from the thermal power plants.

(i) Name any two harmless gases released.

(ii) Name the most widely used device of removing particulate pollutants from the air. Explain how the device is used.

22. (a) Draw a schematic representation of the structure of a transcription unit and show the following in it:

(i) Direction in which the transcription occurs

(ii) Polarity of the two strands involved

(iii) Template strand (iv) Terminator gene

(b) Mention the function of promoter gene in transcription.

OR

(a) In human genome which one of the chromosomes has the most genes and which one has the fewest?

(b) Scientists have identified about 1.4 million single nucleotide polymorphs in human genome. How is the information of their existence going to help the scientists?

27. Plasmid is a boon to biotechnology. Justify this statement quoting the production of human insulin as an example.

SECTION–D

30. (a) How did Griffith explain the transformation of R strain (non-virulent) bacteria into S strain (virulent)?

(b) Explain how MacLeod, McCarty and Avery determined the biochemical nature of the molecule responsible for transforming R strain bacteria into S strain bacteria.

OR

(a) You are given tall pea plants with yellow seeds whose genotypes are unknown. How would you find the genotype of these plants? Explain with the help of cross.

(b) Identify a, b and c in the table given below:

Pattern of inheritance

Monohybrid F1 phenotypic expression

1.

Codominance

a

2.

b

The progeny resembled only one of the parents

3.

Incomplete dominance

c

SET–III

(Uncommon Questions to Set–I and II)

SECTION–A

1. What type of virus causes AIDS? Name its genetic material.

3. Milk starts to coagulate when Lactic Acid Bacteria (LAB) is added to warm milk as a starter. Mention any other two benefits LAB provides.

7. Which of the following is a cyanobacterium that can fix atmospheric nitrogen?

Azospirillum, Oscillatoria, Spirulina.

SECTION–B

9. Study the given portion of double stranded polynucleotide chain carefully. Identify a, b, c and the 5 end of the chain.

d

H

H

|

P

|

C

P

C

|

OH

|

H

H

b

a

c

e

H

H

OH

|

P

|

C

P

C

|

|

H

H

10. Name one plant and the addictive drug extracted from its latex. How does this drug affect the human body?

SECTION–C

19. (a) How does activated sludge get produced during sewage treatment?

(b) Explain how this sludge is used in biogas production.

25. Construct a pyramid of biomass starting with phytoplanktons. Label 3 trophic levels. Is the pyramid upright or inverted? Why?

27. Name the source and the types of cry genes isolated from it for incorporation into crops by biotechnologists. Explain how have these genes brought beneficial changes in the genetically modified crops.

SECTION–D

28. (a) When and how does placenta develop in human female?

(b) How is the placenta connected to the embryo?

(c) Placenta acts as an endocrine gland. Explain.

OR

(a) Trace the development of embryo after syngamy in a dicot plant.

(b) Endosperm development precedes embryo development. Explain.

(c) Draw a diagram of a mature dicot embryo and label cotyledons, plumule, radicle and hypocotyl in it.


CBSE (Foreign)

SET–I




(ii) The question paper consists of four sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C has 9 questions of three marks each whereas Section D is of 3 questions of five marks each.



SECTION–A

1. At which ends do ‘capping’ and ‘tailing’ of hnRNA occur respectively?

2. The meiocyte of rice has 24 chromosomes. How many chromosomes are present in its endosperm?

3. BOD of two samples of water A and B were 120 mg/L and 400 mg/L respectively. Which sample is more polluted?

4.

Mammals

Birds

a

Reptiles

b

Name the unlabelled areas ‘a’ and ‘b’ of the pie chart representing biodiversity of vertebrates showing the proportionate number of species of major taxa.

5. Are the wing of a bird and the forelimb of a horse homologous or analogous? Name the type of evolution that explains the development of such structures.

6. Name the type of interaction seen between whale and the barnacles growing on its back.

7. Which one of the following is used in apiculture:

Hilsa, Apis indica, Sonalika

8. The following statements (i), (ii) and (iii) seem to describe the water-pollinated submerged plants. Which one of these statements is incorrect?

(i) The flowers do not produce nectar.

(ii) The pollen grains have mucilaginous covering.

(iii) The brightly coloured female flowers have long stalk to reach the surface.

SECTION–B

9. Name the source organism from which Ti plasmid is isolated. Explain the use of this plasmid in biotechnology.

10. (a) Explain the property that prevents normal cells from becoming cancerous.

(b) All normal cells have inherent characteristic of becoming cancerous. Explain.

11. In the T.S. of a mature anther given below, identify “a” and “b” and mention their function.

a

b

12. Name the category of codons UGA belongs to. Mention another codon of the same category. Explain their role in protein synthesis.

13. How do automobiles fitted with catalytic converters reduce air pollution? Suggest the best fuel for such vehicles.

14. List the specific symptoms of pneumonia. Name the causative organism.

OR

How does spleen act as a lymphoid organ? Explain.

15. How does the Mediterranean orchid Ophrys ensure its pollination by bees?

16. Highlight any four advantages of genetically modified organisms (GMOs).

17. What is colostrum? Why is it important to be given to the newborn infants?

18.

i

p

o

z

y

a

M

(a) Name the molecule ‘M’ that binds with the operator.

(b) Mention the consequences of such binding.

(c) What will prevent the binding of the molecule ‘M’ with the operator gene? Mention the event that follows.

SECTION–C

19.

(a) Identify the figure.

(b) Name the initial cell from which this structure has developed.

(c) Draw the next mature stage and label the parts.

20. A particular species of wild cat is endangered. In order to save them from extinction, which is a desirable approach in situ or ex situ? Justify your answer and explain the difference between the two approaches.

21. (a) What is EcoRI? What does ‘R’ represent in this?

(b) Give the palindromic nucleotide sequence recognised by it.

(c) Explain its action.

22.

SER

C

G A G C U G A G U U A A

a

a'

(a) Identify the polarity from a to a' in the above diagram and mention how many more amino acids are expected to be added to this polypeptide chain.

(b) Mention the DNA sequence coding for serine and the anticodon of tRNA for the same amino acid.

(c) Why are some untranslated sequence of bases seen in mRNA coding for a polypeptide? Where exactly are they present on mRNA?

23. Why is predation required in a community of different organisms?

24. (a) Name the virus that causes AIDS in humans.

(b) Explain the sequence of events that follows when this virus attacks to cause immune deficiency in humans.

In one family, each of the four children has a different blood group. Their mother is group A and the father is group B. Explain this pattern of inheritance with the help of a cross along with the genotypes.

OR

Who proposed chromosomal theory of inheritance? Point out any two similarities in the behaviour of chromosomes and genes.

26.

(a)

(b)

What do these pictures ‘a’ and ‘b’ illustrate with reference to evolution? Explain.

27. Draw and complete the following model of carbon cycle filling a, b, c, d, e and f.

CO2

Atmosphere

Food

c

d

a

b

e

Plants

Animals

f

Calcareous sediments

SECTION–D

28. (a) Explain the observations of Meselson and Stahl when

(i) they cultured E. coli in a medium containing 15 NH 4 Cl for a few generations and centrifuged the content.

(ii) they transferred one such bacterium to the normal medium of NH 4 Cl.

(b) What does the above experiment prove?

(c) Which is the first genetic material identified?

OR

Inheritance pattern of flower colour in garden pea plant and snapdragon differs. Why is the difference observed? Explain showing the crosses.

29. (a) Draw a labelled diagram of a mature embryo sac of an angiosperm.

(b) Why does a pollen grain possess two male gametes? Explain.

OR

Study the flow chart given below. Name the hormones involved at each stage and explain their role.

Ovulation

Pregnancy

Placenta

Foetal growth

Lactation

Parturition

30. (a) Why are engineered vectors preferred by biotechnologists for transferring the desired genes into another organism?

(b) Explain how do “ori”, “selectable markers” and “cloning sites” facilitate cloning into a vector.

OR

17. How is a transgenic tobacco plant protected against Meloidegyne incognitia?

18. Explain the procedure of making such plants.

SET–II


SECTION–A

2. Why is a coconut plant referred to as monoecious?

5. Are flippers of penguin and dolphin homologous or analogous? What type of evolution has brought such a similarity in them?

8. Which of the following is the semi-dwarf wheat that is high yielding and disease resistant? Pusa Shubra, Kalyan Sona, Ratna.

SECTION–B

13. Differentiate between a template strand and a coding strand of DNA.

15. (a) How is Cuscuta adapted to be a parasitic plant?

(b) Why do cattle avoid browsing on Calotropis plants? Explain.

SECTION–C

22. How is innate immunity different from the immunity that you acquire through vaccines? Describe any two ways by which innate immunity can be accomplished.

25. Name the source of gonadotropins in human females. Explain the changes brought about in the ovary by these hormones during menstrual cycle.

27. Why are (i) alien species invasion and (ii) loss of habitat and fragmentation considered to be the major cause of loss of biodiversity? Explain with the help of one example each.

SECTION–D

28. (a) Draw a labelled diagram of L.S. of a flower to show the growth of pollen tube reaching egg apparatus.

(b) Pistil of a flower does not accept pollen from any plant other than from its own kind. How does it happen? Explain.

OR

(a) Given below is the T.S. of human ovary. Identify the following in the diagram:

e

b

a

c

d

(i) Corpus luteum(ii) Secondary oocyte(iii) Antrum

(iv) Primary follicle(v) Primary oocyte

(b) Explain the changes the primary oocyte undergoes while in different follicular stages before ovulation.

SET–III


SECTION–A

1. Name the type of pollination as a result of which genetically different types of pollen grains of the same species land on the stigma.

3. Are the thorns of Bougainvillea and tendrils of Cucurbita homologous or analogous? What type of evolution has brought such a similarity in them?

7. Which of the the following produces single cell proteins?

Sonalika, Spirulina, Saccharomyces.

SECTION–B

10. How is Darwin’s concept of evolution different from that of de Vries?

15. Identify the curves ‘a’ and ‘b’ shown in the graph given below. List the conditions responsible for growth patterns ‘a’ and ‘b’.

a

density

k

b

Population

(N)

Time (t)

Population growth curve

SECTION–C

19. How are assisted reproductive technologies helpful to humans? How are ZIFT and GIFT different from intra uterine transfers? Explain.

25. (a) Baculoviruses are excellent candidates for integrated pest management in an ecologically sensitive area. Explain giving two reasons.

(b) What is organic farming? Why is it suggested to switch over to organic farming?

27. How did Eli Lilly Company go about preparing the human insulin? How is the insulin thus produced different from that produced by the functional human insulin gene?

SECTION–D

29. Explain the steps of DNA fingerprinting that will help in processing of the two blood samples A and B picked up from the crime scene.

OR

A particular garden pea plant produced only violet flowers. It may or may not be homozygous dominant for the trait. How would you ensure its genotype? Explain with crosses.


CBSE (DELHI)

SET–I




(ii) This question paper consists of four sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C is of 9 questions of three marks each and Section D is of 3 questions of five marks each.



SECTION–A

1. A bilobed, dithecous anther has 100 microspore mother cells per microsporangium. How many male gametophytes this anther can produce?

2. Mention two functions of the codon AUG.

3. Name the scientist who disproved spontaneous generation theory.

4. What is it that prevents a child to suffer from a disease he/she is vaccinated against? Give one reason.

5. Why is the enzyme cellulase used for isolating genetic material from plant cells but not for animal cells?

6. Name a molecular diagnostic technique to detect the presence of a pathogen in its early stage of infection.

7. If 8 individuals in a laboratory population of 80 fruit flies died in a week, then what would be the death rate of population for the said period?

8. Mention one positive and one negative application of amniocentesis.

SECTION–B

9. A moss plant produces a large number of antherozoids but relatively only a few egg cells. Why?

10. Mention the reasons for difference in ploidy of zygote and primary endosperm nucleus in an angiosperm.

11. How does an electrostatic precipitator work to remove particulate pollutants released from the thermal power plants?

12. Name the type of food chains responsible for the flow of larger fraction of energy in an aquatic and a terrestrial ecosystem, respectively. Mention one difference between the two food chains.

13. How does a test-cross help in identifying the genotype of the organism? Explain.

14. Name the host and the site where the following occur in the life-cycle of a malarial parasite:

(a) Formation of gametocytes

(b) Fusion of gametocytes

15. Honey collection improves when beehives are kept in crop-fields during the flowering season. Explain.

OR

How does addition of a small amount of curd to fresh milk help in the formation of curd?

Mention a nutritional quality that gets added to the curd.

16. Why is the introduction of genetically engineered lymphocytes into an ADA deficiency patient not a permanent cure? Suggest a possible permanent cure.

17. How does the floral pattern of Mediterranean orchid Ophrys guarantee cross pollination?

18. In the biosphere immense biological diversity exists at all levels of biological organisation. Explain any two levels of biodiversity.

SECTION–C

19. Draw a longitudinal section of a post-pollinated pistil showing entry of pollen tube into a mature embryo-sac. Label filiform apparatus, chalazal end, Hilum, antipodals, male gametes and secondary nucleus.

OR

Draw a labelled sectional view of seminiferous tubule of a human male.

20. During his studies on genes in Drosophila that were sex-linked. T.H. Morgan found F2 population phenotypic ratios deviated from expected 9 : 3 : 3 : 1. Explain the conclusion he arrived at.

21. Describe the initiation process of transcription in bacteria.

22. Explain convergent and divergent evolution with the help of one example of each.

23. Name the type of human cell HIV attacks on its entry into the body. Explain the events that occur in the cell which further lead to cause immunodeficiency syndrome.

24. Explain the efforts which must be put in to improve health, hygiene and milk yield of cattle in a dairy farm.

25. Identify a, b, c, d, e and f in the table given below:

Organism

Bioactive Molecule

Use

1.

Monascus perpureus (yeast)

a

b

2.

c

d

antibiotic

3.

e

Cyclosporin A

f

26. EcoRI is used to cut a segment of foreign DNA and that of a vector DNA to form a recombinant DNA. Show with the help of schematic diagrams.

(i) The set of palindronic nucleotide sequence of base pairs the EcoRI will recognise in both the DNA segments. Mark the site at which EcoRI will act and cut both the segments.

(ii) Sticky ends formed on both the segments where the two DNA segments will join later to form a recombinant DNA.

27. How does RNA interference help in developing resistance in tobacco plant against nematode infection?

SECTION–D

28.(i) How does a Chromosomal disorder differ from a Mendelian disorder? (ii) Name any two chromosomal aberration associated disorders.

(iii) List the characteristics of the disorders mentioned above that help in their diagnosis.

OR

Fitness is the end result of the ability to adapt and get selected by nature. Explain with suitable example.

29. When and where are primary oocytes formed in a human female? Trace the development of these oocytes till ovulation (in menstrual cycle). How do gonadotropins influence this developmental process?

OR

(iv) Explain the events taking place at the time of fertilization of an ovum in a human female.

(v) Trace the development of the zygote upto its implantation in the uterus.

(vi) Name and draw a labelled sectional view of the embryonic stage that gets implanted.

30. Draw and explain a logistic curve for a population of density (N) at time (t) whose intrinsic rate of natural increase is (r) and carrying capacity is (k).

OR

Describe the process of decomposition of detritus under the following heads: Fragmentation;

leaching; catabolism; humification and mineralisation.

SET–II


SECTION–A

6. An anther with malfunctioning tepetum often fails to produce viable male gametophytes. Give one reason.

8. In a pond there were 20 Hydrilla plants. Through reproduction 10 new Hydrilla plants were added in a year. Calculate the birth rate of the population.

SECTION–B

9. Biodiversity must be conserved as it plays an important role in many ecosystem services that nature provides. Explain any two services of the ecosystem.

14. How many haploid cells are present in a mature female gametophyte of a flowering plant? Name them.

15. When a tall pea plant was selfed, it produced one-fourth of its progeny as dwarf. Explain with the help of a cross.

16. Chlorofluorocarbons (CFCs) are widely used as refrigerants. Then why is it suggested to reduce its emission as far as possible? Explain.

SECTION–C

22.

N

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

C

S

S

S

S

S

S

S

S

S S S

S

'b'

'a'

S

S

CC

Identify a, b and c in the schematic diagram of an antibody given above answer the questions.

(i) Write the chemical nature of an antibody.

(ii) Name the cells that produce antibodies in humans.

(iii) Mention the type of immune response provided by an antibody.

26. Describe the elongation process of transcription in bacteria.

SECTION–D

29. Explain the causes, inheritance pattern and symptoms of any two Mendelian genetic disorders.

OR

(i) Natural selection operates when nature select for fitness. Explain.

(ii) The rate of appearance of new forms is linked to the lifespan of an organism. Explain with the help of a suitable example.

SET–III


SECTION–A

2. How do animals like fish and snails avoid summer related unfavourable conditions?

3. In a pond there were 200 frogs. 40 more were born in a year. Calculate the birth rate of the population.

SECTION–B

9. Where does triple fusion take place in a flowering plant? Why is it so called? Mention its significance.

10. Why certain regions have been declared as biodiversity “hot spots” by environmentalists of the world? Name any two “hot spot” regions of India.

13. Study the given aquatic food chain and answer the questions that follow:

Fish eating birds (DDT 5 ppm)

Large fish

(DDT 2 ppm)

Small fish (DDT 0.5 ppm)

Zooplankton (DDT 0.04 ppm)

Water (DDT 0.003 ppm)

(i) Give reasons why there is a continuous increase in the DDT content in different trophic levels of the chain.

(ii) Name the phenomenon responsible for the increase in DDT content.

19. Why are F2 phenotypic and genotypic ratios same in a cross between red-flowered snapdragon and white-flowered snapdragon plants. Explain with the help of a cross.

SECTION–C

20. Describe the termination process of transcription in bacteria.

26. An antibody molecule is represented as H2L2. Explain.

SECTION–D

30. Write the symptoms of haemophilia and sickle-cell anaemia in humans. Explain how the inheritance pattern of the two diseases differs from each other.

OR

(a) Write the Hardy-Weinberg principle.

(b) Explain the three different ways in which natural selection can affect the frequency of a heritable trait in a population shown in the graph given below.

Medium-sized

withphenotype

Number of individuals

Phenotypes favoured by

natural selection

individuals are favoured

Trait


CBSE (ALL INDIA)

Time allowed: 3 hoursMax. Marks: 70



(ii) This question paper consists of four sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C is of 9 questions of three marks each and Section D is of 3 questions of five marks each.



SET–I

SECTION–A

1. Mention the site where syngamy occurs in amphibians and reptiles respectively.

2. How is snow-blindness caused in humans?

3. Name one autosomal dominant and one autosomal recessive Mendelian disorder in humans.

4. How is the action of exonuclease different from that of endonuclease?

5. India has more than 50,000 strains of rice. Mention the level of biodiversity it represents.

6. Mention the information that the health workers derive by measuring BOD of a water body.

7. Name the enzyme involved in the continuous replication of DNA strand. Mention the polarity of the template strand.

8. Offsprings derived by asexual reproduction are called clones. Justify giving two reasons.

SECTION–B

9. Mention the role of ribosomes in peptide-bond formation. How does ATP facilitate it?

10. How do copper and hormone releasing IUDs act as contraceptives? Explain.

11. If you squeeze a seed of orange you might observe many embryos of different sizes. How is it possible? Explain.

12. A recombinant DNA is formed when sticky ends of vector DNA and foreign DNA join. Explain how the sticky ends are formed and get joined.

13. (i) Mention the number of primers required in each cycle of polymerase chain reaction (PCR). Write the role of primers and DNA polymerase in PCR.

(ii) Give the characteristic feature and source organism of the DNA polymerase used in PCR.

14. Define the term 'health'. Mention any two ways of maintaining it.

OR

Why does a doctor administer tetanus antitoxin and not a tetanus vaccine to a child injured in a

roadside accident with a bleeding wound? Explain.

15. Giving two reasons explain why there is more species biodiversity in tropical latitudes than in temperate ones.

16. Name an opioid drug and its source plant. How does the drug affect the human body?

17. Mention the major cause of air pollution in metro cities. Write any three ways by which it can be reduced.

18. How did Eli Lilly synthesise the human insulin? Mention one difference between this insulin and the one produced by the human pancreas.

SECTION–C

19. (i) Write the characteristic features of anther, pollen and stigma of wind pollinated flowers.

(ai) How do flowers reward their insect pollinators? Explain.

20. (i) Why are grasshopper and Drosophila said to show male heterogamity? Explain.

(ai) Explain female heterogamity with the help of an example.

21. In a series of experiments with Streptococcus and mice F. Griffith concluded that R-strain bacteria had been transformed. Explain.

22. (a) How does the Hardy-Weinberg's expression (p2 2pq q 2 1) explain that genetic equilibrium is maintained in a population?

(b) List any two factors that can disturb the genetic equilibrium.

23. Mention the name of the causal organism, symptoms and the mode of transmission of the disease Amoebiasis.

24. (i) Mention the property that enables the explants to regenerate into a new plant.

(ai) A banana herb is virus-infected. Describe the method that will help in obtaining healthy banana plants from this diseased plant.

25. Mention the product and its use produced by each of the microbes listed below:

(i) Streptococcus

(ii) Lactobacillus

(iii) Saccharomyces cerevisiae

26. (i) Name the organism in which the vector shown in inserted to get the copies of the desired gene.

(ii) Mention the area labelled in the vector responsible for controlling the copy number of the inserted gene.

(iii) Name and explain the role of a selectable marker in the vector shown.

Cla IHind III

Eco R I

Pvu I

Bam H I

Pst I

ampRtetR

Sal I

pBR322

ori

rop

Pvu II

OR

Name the insect pest that is killed by the products of cryIAc gene. Explain how the gene makes

the plant resistant to the insect pest.

27. How do organisms like fungi, zooplanktons and bears overcome the temporary short-lived climatic stressful conditions? Explain.

SECTION–D

28. Describe in sequence the events that lead to the development of a 3-celled pollen grain from microspore mother cell in angiosperms.

OR

(a) Give a schematic representation showing the events of spermatogenesis in human male.

(b) Describe the structure of a human sperm.

29. (a) State the law of independent assortment.

(b) Using Punnett Square demonstrate the law of independent assortment in a dihybrid cross involving two heterozygous parents.

OR

How did Alfred Hershey and Martha Chase arrive at the conclusion that DNA is the genetic

material?

30. (a) Why are herbivores considered similar to predators in the ecological context? Explain.

(b) Differentiate between the following interspecific interactions in a population:

(i) Mutualism and Competition

(ii) Commensalism and Amensalism

OR

(a) Trace the succession of plants on a dry bare rock.

(b) How does phosphorus cycle differ from carbon cycle?

SET–II


SECTION–A

2. Write the genotype of (i) an individual who is carrier of sickle cell anaemia gene but apparently unaffected, and (ii) an individual affected with the disease.

6. Mention a characteristic feature and a function of zoospores in some algae.

SECTION–B

9. Placenta acts as an endocrine tissue. Justify.

10. Differentiate between menarche and menopause.

13. List the features that make a stable biological community.

17. Mention how e-waste is produced and disposed off. Write the solution for its treatment.

SECTION–C

21. Explain the process of artificial hybridisation to get improved crop variety in (i) plants bearing bisexual flowers (ii) female parent producing unisexual flowers.

27. Explain the sex determination mechanism in humans. How is it different in birds?

SECTION–D

30. (a) Trace the development of megaspore mother cell up to the formation of a mature embryo-sac in a flowering plant.

(b) Draw a labelled diagram of the structure of mature dicot embryo.

OR

(a) Draw a diagrammatic labelled sectional view of a seminiferous tubule of a human.

(b) Describe in sequence the process of spermatogenesis in humans.

SET–III


SECTION–A

1. A human being suffering from Down’s Syndrome shows trisomy of 21st chromosome. Mention the cause of this chromosomal abnormality.

4. Pea flowers produce assured seed sets. Give a reason.

SECTION–B

13. Differentiate between major structural changes in the human ovary during the follicular and luteal phase of the menstrual cycle.

15. Alien species are a threat to native species. Justify taking examples of an animal and a plant alien species.

17. Explain giving reasons the cause of appearance of peaks ‘a’ and ‘b’ in the graph shown below.

a

Dissolved oxygen

b

CONCENTRATION

B O D

DIRECTION OF FLOW

Sewage discharge

Effect of sewage discharge on some important characteristics of a river

18. Explain the zygote intra fallopian transfer technique (ZIFT). How is intrauterine transfer technique (IUT) different from it?

SECTION–C

20. Explain the mechanism of sex determination in insects like Drosophila and grasshopper.

27. (a) Mention any four strategies adopted by flowering plants to prevent self-pollination.

(b) Why is geitonogamy also referred to as genetical autogamy?

SECTION–D

29. (a) Draw a labelled longisectional view of albuminous ‘seed’.

(b) How are seeds advantageous to flowering plants?

OR

Describe the post-zygotic events loading to implantation and placenta formation in humans. Mention any two functions of placenta.

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nirmaladasar.files.wordpress.com€¦ · Web viewEXAMINATION PAPERS – 2008. CBSE (Delhi) SET–I. Time allowed: 3 hours. Maximum marks: 70. General Instructions: All questions